METHOD FOR PLANARIZING AN INSULATION LAYER IN A SEMICONDUCTOR DEVICE CAPABLE OF OMITTING A MASK PROCESS AND AN ETCHING PROCESS
In a method for planarizing an insulation layer in a semiconductor device, an insulation layer is formed over a semiconductor substrate having a cell region and a peripheral region. The cell region is higher than the peripheral region due to a capacitor formed in the cell region. A metal layer is formed over the insulation layer. The metal layer is chemical mechanical polished to expose the insulation layer portion in the cell region. The exposed insulation layer portion in the cell region is chemical mechanical polishing to planarize the insulation layer, and the planarized insulation layer and the remaining metal layer are chemical mechanical polishing to remove the metal layer remained in the peripheral region. The method for planarizing an insulation layer does not require a separate photosensitive layer forming process or a dry etching process.
The present application claims priority to Korean patent application number 10-2007-0031926 filed on Mar. 30, 2007, which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTIONThe present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for planarizing an insulation layer formed in a structure which causes a height difference between the insulation layer in a cell region and the insulation layer in a peripheral region of a semiconductor device.
A sharp increase in the demand for semiconductor devices has led to the suggestion of various technologies for achieving a high capacity capacitor. The capacitor's structure includes a dielectric film interposed between a storage electrode and a plate electrode. The capacitor's capacity is proportional to the surface area of the electrode and a dielectric constant and is inversely proportional to a space between the electrodes, i.e. a thickness of the dielectric film. Therefore, in order to produce a high capacity capacitor, it is necessary to use a dielectric film having a high dielectric constant, increase a surface area of a storage electrode, or shorten a distance between electrodes.
Currently, a capacitor having a cylindrical structure that ensures a large electrode area with a relatively simple process is largely used as the storage electrode of a capacitor.
An interlayer insulation layer is formed for insulating a plate electrode and a subsequently formed metal wiring. A height difference between the interlayer insulation in the region formed with the capacitor, (i.e. a cell region) and the interlayer insulation in the region formed with no capacitor (i.e. a peripheral region) is caused by the capacitor, which has a large height. To remove this height differential, a planarization of the interlayer insulation layer is implemented for eliminating the height difference caused by the capacitor.
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As described above, in the prior art method for planarizing the insulation layer of a semiconductor device, the interlayer insulation layer in the cell region, which has the larger height, is etched using a photosensitive layer pattern as a mask. The interlayer insulation layer, which already has some of its height removed, is then chemical mechanical polished.
However, in the aforementioned prior art, the mask process and the etching process lengthen the processing time, and the production cost is increased by the cost of a photosensitive layer pattern forming process, both of which raise the unit manufacturing cost.
BRIEF SUMMARY OF THE INVENTIONEmbodiments of the present invention are directed to a method for planarizing an insulation layer, and more particularly to a method for planarizing an insulation layer of a semiconductor device which is capable of omitting a mask process and an etching process when planarizing the insulation layer.
Further, embodiments of the present invention are directed to a method for planarizing an insulation layer of a semiconductor device that decreases a unit manufacturing cost.
In one embodiment, a method for planarizing an insulation layer of a semiconductor device may comprise forming an insulation layer over a semiconductor substrate having a first region and a second region. The portion of the insulation layer in the first region is higher than the portion of the insulation layer in the second region. A metal layer is formed over the insulation layer. The metal layer is chemical mechanical polishing to expose the insulation layer portion in the first region. The exposed insulation layer portion in the first region is chemical mechanical polishing to planarize the insulation layer, and the planarized insulation layer and the remaining metal layer is chemical mechanical polishing to remove the metal layer remained in the region.
The first region is a cell region and the second region is a peripheral region.
The insulation layer may include an oxide.
The metal layer may include tungsten.
The metal layer is formed to a thickness of 200 to 3000 Å.
Chemical mechanical polishing of the metal layer is performed using a metal polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
Chemical mechanical polishing of the exposed insulation layer portion is performed using an insulation layer polishing slurry having a polishing selection ratio between the metal layer and the insulation layer of 1:10 to 1:200.
Chemical mechanical polishing of the planarized insulation layer and the remaining metal layer is performed using a metal polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
In another embodiment, a method for planarizing an insulation layer in a semiconductor device may comprise forming a capacitor over a cell region of a semiconductor substrate having the cell region and a peripheral region. Forming an insulation layer over a semiconductor substrate having a height difference between the cell region and the peripheral region caused by the capacitor (i.e. the cell region is higher than the peripheral region). A metal layer is then formed over the insulation layer. The metal layer is chemical mechanical polishing to expose an insulation layer portion in the cell region. The exposed insulation layer portion in the cell region is chemical mechanical polishing to planarize the insulation layer, and the planarized insulation layer and the remaining metal layer is chemical mechanical polishing to remove the metal layer remained in the peripheral region.
The insulation layer includes an oxide.
The metal layer includes tungsten.
The metal layer is formed to a thickness of 200 to 3000 Å.
The chemical mechanical polishing of the metal layer is performed using a tungsten polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
The chemical mechanical polishing of the exposed insulation layer portion is performed using an insulation layer polishing slurry having a polishing selection ratio between the metal layer and the insulation layer of 1:10 to 1:200.
The chemical mechanical polishing of the planarized insulation layer and the remaining metal layer is performed using a metal polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
A preferred embodiment of the present invention is directed to a method for planarizing an insulation layer in a semiconductor device, in which a metal layer, such as a tungsten layer, is formed over the insulation layer, and the insulation layer is planarized by using a polishing selection ratio between the insulation layer and the tungsten layer.
In the present invention, it is not necessary to form a separate photosensitive layer pattern for planarizing the insulation layer, and it is also possible to omit a dry etching of the insulation layer. Since the planarization of the insulation layer can be accomplished using only the chemical mechanical polishing process, it is possible to simplify the manufacturing process and reduce the unit manufacturing cost. Additionally, because the dry etching process of the insulation layer can be omitted, it is possible to prevent etching defects, and thus an increase in the manufacturing yield of a device can be expected.
Hereafter, a method for planarizing an insulation layer in a semiconductor device in accordance with an embodiment of the present invention will be described with reference to the attached drawings.
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At this time, the tungsten layer formed between the cell region and the peripheral region, i.e. on the stepped side wall, is easily removed by a mechanical element during the second chemical mechanical polishing and thus is of little consequence. The tungsten layer formed in the peripheral layer acts as a polishing stop layer, and thus uniformity in the substrate can be ensured.
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As is apparent from the above description, in an embodiment of the present invention, a tungsten layer is deposited over a stepped insulation layer and a chemical mechanical polishing process is performed several times using slurries having different polishing selection ratios between the insulation layer and the metal layer. An embodiment of the present invention makes it possible to planarize the insulation layer without a separate photosensitive layer forming process and dry etching process. Therefore, in an embodiment of the present invention, it is possible to accomplish a planarization of an insulation layer using only a chemical mechanical polishing. Therefore, when compared to the prior art, the number of total processes and the production cost are reduced and concerns of device defect due to dry etching are eliminated. As a result, it is possible to lower the unit manufacturing cost and increase the manufacturing yield of a device.
Although a specific embodiments of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and the spirit of the invention as disclosed in the accompanying claims.
Claims
1. A method for planarizing an insulation layer in a semiconductor device, comprising the steps of:
- forming an insulation layer over a semiconductor substrate having a first region and a second region, wherein a portion of the insulation layer located in the first region is higher than a portion of the insulation layer located in the second region;
- forming a metal layer over the insulation layer;
- chemical mechanical polishing the metal layer to expose the insulation layer portion in the first region;
- chemical mechanical polishing the exposed insulation layer portion in the first region to planarize the insulation layer; and
- chemical mechanical polishing the planarized insulation layer and the remaining metal layer to remove the remaining metal layer in the second region.
2. The method for planarizing an insulation layer in a semiconductor device according to claim 1, wherein the first is a cell region and the second region is a peripheral region.
3. The method for planarizing an insulation layer in a semiconductor device according to claim 1, wherein the insulation layer includes an oxide.
4. The method for planarizing an insulation layer in a semiconductor device according to claim 1, wherein the metal layer includes tungsten.
5. The method for planarizing an insulation layer in a semiconductor device according to claim 1, wherein the metal layer is formed to a thickness of 200 to 3000 Å.
6. The method for planarizing an insulation layer in a semiconductor device according to claim 1, wherein the step of chemical mechanical polishing the metal layer to expose the insulation layer portion in the first region is performed using a metal polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
7. The method for planarizing an insulation layer in a semiconductor device according to claim 1, wherein the step of chemical mechanical polishing the exposed insulation layer portion in the first region is performed using a insulation layer polishing slurry having a polishing selection ratio between the metal layer and the insulation layer of 1:10 to 1:200.
8. The method for planarizing an insulation layer in a semiconductor device according to claim 1, wherein the step of chemical mechanical polishing the planarized insulation layer and the remaining metal layer is performed using a metal polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
9. A method for planarizing an insulation layer in a semiconductor device, comprising the steps of:
- forming a capacitor over a cell region of a semiconductor substrate having the cell region and a peripheral region;
- forming an insulation layer over the semiconductor substrate and the capacitor, wherein a portion of the insulation layer located in the cell region is higher than a portion of the insulation region located in the peripheral region due to the capacitor;
- forming a metal layer over the insulation layer;
- chemical mechanical polishing the metal layer to expose an insulation layer portion in the cell region;
- chemical mechanical polishing the exposed insulation layer portion in the cell region to planarize the insulation layer; and
- chemical mechanical polishing the planarized insulation layer and the remained metal layer to remove the metal layer remained in the peripheral region.
10. The method for planarizing an insulation layer in a semiconductor device according to claim 8, wherein the insulation layer includes an oxide.
11. The method for planarizing an insulation layer in a semiconductor device according to claim 8, wherein the metal layer includes tungsten.
12. The method for planarizing an insulation layer in a semiconductor device according to claim 8, wherein the metal layer is formed to a thickness of 200 to 3000 Å.
13. The method for planarizing an insulation layer in a semiconductor device according to claim 8, wherein the step of chemical mechanical polishing the metal layer to expose the insulation layer portion in the cell region is performed using a metal polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
14. The method for planarizing an insulation layer in a semiconductor device according to claim 8, wherein the step of chemical mechanical polishing the exposed insulation layer portion in the cell region s performed using a insulation layer polishing slurry having a polishing selection ratio between the metal layer and the insulation layer of 1:10 to 1:200.
15. The method for planarizing an insulation layer in a semiconductor device according to claim 8, wherein the step of chemical mechanical polishing the planarized insulation layer and the remaining metal layer is performed using a metal polishing slurry having a polishing selection ratio between the insulation layer and the metal layer of 1:10 to 1:200.
Type: Application
Filed: Nov 14, 2007
Publication Date: Oct 2, 2008
Inventors: Hyung Hwan KIM (Gyeonggi-do), Jong Goo JUNG (Gyeonggi-do)
Application Number: 11/939,631
International Classification: H01L 21/4763 (20060101);